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	<center><img src="images/comet-period-header.png" alt= "Comet Period header" title="This is the page header for Comet Periods."/></center>
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	<b>Short Period and Long Period Comets</b>
	<P>	
		An orbit period is the time it takes to complete the path of the orbit. Some comets travel in an orbit that can take several years. Other comets travel in orbits that can take millions of years! Scientists believe that short and long period comets were formed in different areas of the solar system. They believe that short-period comets must have been formed closer to the Sun because they were formed under warmer conditions that long-period comets. This is new information that scientists learned while studying comets.   
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	<img id="left" img src="images/kuiper-belt.png" alt="Kuiper Belt" title="Kuiper Belt"/>
	<b>Short-period comets</b> 
	<P>
	Short period comets are called periodic comets. These comets are in orbits which take a period of 200 years or less to complete. Short period comets begin in the Kuiper belt. The Kuiper belt is located beyond Neptune. Perhaps the most famous short period comet is Halley's Comet. 
		
		
	The largest concentration of asteroids in our solar system is located in a "belt" revolving between Jupiter and Mars. Some asteroids have escaped this belt and as a result can be seen traveling in the solar system, many seen with space probes and Earth telescopes. The recent studies of asteroids has revealed that they are not barren rocks as once believed. Instead, scientists have discovered that asteroids contain water on the surface in the form of ice.
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	<img id="right" img src="images/long-period-comet.png" alt="Long-period comet" title="Long-period comet"/>
	
	<b>Long-period comets</b>
	<p>
		Some comets are on very long orbits, lasting at least 200 years and even for going millions of years!  These comets are known as long-period comets, and may be seen once by a human and never seen again. This is because after they pass through our solar system they get flung out into an area of space beyond our solar system. The orbit of a long-period comet can be strange because it is very long and moves in an unusual pattern. One long-period comet is called Comet West, which is thought to be on an orbital period of 6 million years! 
	
	</P>
	
	
	<P>	One comet named McNaught was discovered in 2007. McNaught is considered a long-period comet because its orbit 
		is estimated to be about 92,600 years. Wow - that is a long time! This space is called interstellar space. 
		It is believed that long-period comets started from an area called the Oort Cloud.  
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            <p>Can you image traveling through space in an orbit that last more than 200 years, or even millions?  Check out this page to learn more about so called "short period" and "long period" comets.</p>
          
          
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